Glass.



WILLIAM C. TAYLOR, OF COBNING, NEW YORK, ASSIGNOR TO CORNING GLASS WORKS, OF COBNING, NEW YORK, A CORPORATION OF NEW YORK.

GLASS.

- Specification of Letters Patent.

Patented July 25, 1916.

No Drawing. Application filed September ,17, 1914, Serial No, 862,252. Renewed December. 27, 1915. Serial No. 68,920.

To all whom it may concern:

Be it known that I, (VILLIAM C. TAYLOR, a citizen of the United States of America, and a resident of Corning, New York, have invented certain new and useful Improvements in Glass, of which the following is a specification. I

My invention relates to a composition for the production of a glass of a low expansion co-efficient, and inasmuch as one of the uses had in view for this glass is the manufacture from it of culinary vessels, my invention also contemplates the production of a glass of a low expansion and of high stability.

Glasses of very low co-elficient expansion can be obtained by formulae now known, but the difficulty experienced in such compositions is that if their expansion co-eflicient is sufficiently low for the practical purposes, their temperature of fusing is so high as to preclude their economical'working, and preventitheir use for the manufacture of Ware which I have in mind. I have discovered, however, that the addition of a small amount of lithia reduces the temperature of fusion of a glass mixture to a very great degree, and that this is so pronounced that although lithia has a high expansion factor, still it can be used in such small quantities as not to appreciably increase the expansion coefficient of the mixture, While at the same time, materially reducing the fusing temperature. I have further discovered that lithia in the composition which I herein describe is of value in increasing the stability of the glass, although the glass herein referred to is a boro-silicate of very low ex- 'pansion'. Glasses of such compositions, especially when of high boric acid contents, are generally unstable, and subject to decomposition.

The following are examples of the compositions of several glasses made in accordance wlth this 1nvent1on:

The expansion co-eflicient of composition A above named, I have found to be .0000029, of B, .0000040, and of 0, .0000056. It will be noted that all of the above com-v positlons contain a comparatively large per cent. of boric oxid; and that all of them are boro-silicates. Glasses made fromcomposr tions of the formula: above given are ex- I tremely useful in the manufacture of glass articles exposed to extreme variation of temperature and to attacks by steam or other chemical action,- this being by reason of their low co-eflicient of expansion and their stability.

The presence of the alumina in compositions B and C is useful in preventing crys- Witnesses:

E. O. SULLIVAN, G. WILLIS DRAKE.

WILLIAM o. TAYLOR. 

